title: Interaction of synthetic peptide octarphin (TPLVTLFK) with human blood lymphocytes.
abstract: The synthetic peptide octarphin (TPLVTLFK) corresponding to the sequence 12-19 of β-endorphin, a selective agonist of non-opioid β-endorphin receptor, was labeled with tritium to specific activity of 29 Ci/mmol. The analysis of [(3) H]octarphin binding to human T and B lymphocytes separated from normal human blood revealed the existence of one type of high-affinity binding sites (receptors): Kd 3.0 and 3.2 nM, respectively. Besides unlabeled octarphin, unlabeled β-endorphin possessed the ability to inhibit the specific binding of [(3) H]octarphin to Т and B lymphocytes (Ki 1.9 and 2.2 nМ, respectively). Tests of the specificity of the receptors revealed that they are not sensitive to naloxone, α-endorphin, γ-endorphin, [Met(5) ]enkephalin, and [Leu(5) ]enkephalin. Thus, both T and B lymphocytes from normal human blood express non-opioid receptor for β-endorphin. Binding of the hormone to the receptor provides a fragment 12-19.
authors.affiliation: Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Science Avenue, 6, Pushchino, Moscow Region, 142290, Russia.
authors.forename: Yuliia N
authors.initials: YN
authors.lastname: Nekrasova
authors.forename: Elena V
authors.initials: EV
authors.lastname: Navolotskaya
mesh_terms: D000595:Amino Acid Sequence; D001402:B-Lymphocytes / Q000378:metabolism*; D001665:Binding Sites; D001667:Binding, Competitive; D002478:Cells, Cultured; D006801:Humans; D020128:Inhibitory Concentration 50; D009270:Naloxone / Q000378:metabolism / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000378:metabolism / Q000494:pharmacology; D009842:Oligopeptides / Q000378:metabolism* / Q000494:pharmacology; D011485:Protein Binding; D011957:Receptors, Opioid / Q000819:agonists / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism*; D001615:beta-Endorphin / Q000378:metabolism / Q000494:pharmacology
chemical_list: D009292:Narcotic Antagonists; D009842:Oligopeptides; D011957:Receptors, Opioid; C555005:octarphin; D009270:Naloxone; D001615:beta-Endorphin
keywords: lymphocyte; peptide; receptor; β-endorphin